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Volume 2, Supplement 1, 2002

Volume 2, Supplement 1, 2002

Table of Contents

Current Colorectal Cancer Screening Strategies: Overview and Obstacles to Implementation
Colorectal cancer is the second leading cause of cancer death but is largely preventable. Current strategies to prevent colorectal cancer vary considerably with regard to effectiveness, up-front costs, risks, and invasiveness. Current levels of participation in colorectal cancer screening in the U.S. population are low. Both physician and patient attitudes contribute to low levels of screening uptake. New colorectal cancer tests are one mechanism to improve adherence. Virtual colonoscopy may have an important impact if techniques to perform it without bowel preparation can be developed. Stool-based DNA testing is likely to be the most effective entirely noninvasive strategy and will be easier for patients to perform than fecal occult blood testing. The potential for improvements in the technology are substantial, and data from second-generation assays have already been reported. The cost-effectiveness of new strategies needs further evaluation. [Rev Gastroenterol Disord. 2002;2(suppl 1):S2–S11]
Molecular Basis for Stool DNA Tests for Colorectal Cancer: A Primer for Clinicians
Cancers develop as a result of alterations in genes that regulate growth, survival, and other cellular behaviors. Colorectal cancers develop through one of at least three different pathways, termed chromosomal instability, microsatellite instability, and the CpG island methylator phenotype. Although there is some overlap, these pathways tend to inactivate different sets of tumor suppressor genes and tend to have somewhat different biological behaviors. Tumor cells and DNA are shed into the fecal stream, and uniquely mutated genes can be identified that would indicate the likely presence of a neoplasm in the gastrointestinal tract. By understanding the pathways to tumor development, the target genes involved, and the mechanisms underlying genomic instability, it will be possible to implement strategies to detect and treat the different types of colorectal cancer. [Rev Gastroenterol Disord. 2002;2(suppl 1):S12–S19]
Stool-Based DNA Tests for Colorectal Cancer: Clinical Potential and Early Results
Stool-based DNA testing is a promising new diagnostic tool with the potential to improve the overall effectiveness of colorectal cancer screening. Early clinical studies suggest that multi-target, DNA-based stool tests are capable of detecting both premalignant adenomas and cancers with high sensitivity and specificity. Screening compliance could be enhanced by the user-friendly features of stool-based DNA testing which include: the testing is noninvasive, requires no cathartic bowel preparation or diet or medication restrictions, and requires just a single specimen per screen. Large, multicenter, comparative studies addressing the performance of stool-based DNA testing in the general population will soon be completed and will promise to validate the readiness of this approach for widespread application. [Rev Gastroenterol Disord. 2002;2(suppl 1):S20–S26]
Successful Colorectal Cancer Screening Starts with Primary Care
Colorectal cancer screening is effective. Screening rates remain low, but that will change. All guidelines now recommend colorectal cancer screening, the value of screening is being promoted in the popular media, and insurers are beginning to pay for screening tests. For screening programs to be successful, good intentions must be backed by reminder systems, readily available patient information, and other changes in office practice. Currently recommended screening options accommodate a broad range of patient preferences and save lives, but none is ideal. Newer tests, such as virtual colonoscopy and stool-based DNA tests, will help if they offer greater sensitivity, specificity, or patient acceptability than current screening options. [Rev Gastroenterol Disord. 2002;2(suppl 1):S27–S34]